This invention relates to the preparation of alkanol amides of fatty acids whose acyl groups have from about 8 to about 20 carbon atoms, to mixtures of such amides, and to uses of such mixtures.
The production of alkanol amides by a reaction with alkanol amines of esters derived from natural oils and fats in a base catalyzed process has been known for some time. The process is described in U.S. Pat. Nos. 2,464,094; 2,877,246; 3,107,258; 3,257,436 and 3,395,162 and in J. Am. Chem. Soc. 64, 2498 (1942). The process produces monoalkanol amides when using monoalkanol amines as reactant while it produces dialkanol amides when using dialkanol amines as reactant.
The monoalkanol amides are useful in detergent compositions as described in U.S. Pat. Nos. 2,383,737 and 3,332,878. The dialkanol amides also are useful in detergent compositions as described in U.S. Pat. Nos. 2,607,740 and 2,870,091.
In many instances the dialkanol amides are preferred because of convenient, low, melting points which permit handling as liquids at ordinary temperatures of 25.degree.-75.degree. C. Unfortunately, this virtually has required the use of natural source ester materials because there has been no convenient source of usable synthetic esters for the base catalyzed reaction with dialkanol amines as that process is known from the prior art. One of the preferred sources of low cost synthetic source esters is via the catalytic reaction of olefins with CO and alcohol as described for example in U.S. Pat. Nos. 3,168,553. Unfortunately, the esters obtained this way do not react readily with dialkanol amines. An aspect of this invention is the discovery that this trouble is caused by the presence in such synthetic esters of a substantial percentage (15-50 percent) of esters having branched chain acyl groups, many of which acyl groups have .alpha.-ethyl, .alpha.-propyl, .alpha.-butyl and higher alkyl group substitution located in the carbon chain position alpha (.alpha.) to the carbon atom of the ##STR1## group.
To avoid this problem of poor reactivity of branched esters it has been necessary in the past to use the prior art acyl halide route wherein an acid having a desired acyl group such as dodecanoic or tridecanoic is converted to acyl halide, such as acyl chloride, and then the acyl halide is reacted with dialkanol amine. U.S. Pat. Nos. 2,411,434 and 3,503,891 describe such processing.